Coil spring nonrepeat keylever dobber



O United States Patent [72] inventors Allison ll. Caudill; [56] References Cited Willie Golf, Jr., Lexington, Kentucky UNlTED STATES PATENTS [21] P No. 745,250 2,807,345 9 1957 Nimlitch [221 PM My 2 978 086 4/1961 l-lickerson [45] Patented Nov. 3, 1970 73 A I t n m i M hi 3,021,937 2/1962 Seymour l 1 6' 3' us ac has 3,045,799 7/1962 Seymour et al. Y k 3,086,635 4/1963 Palmer 1 3,289,804 12/1966 Schaefer a corporation of New York Primary Examiner-Edgar S. Burr Attorney- Hanifin and J ancin and E, Ronald Coffman [54] COIL SPRING NON-REPEAT KEYLEVER DOBBER 13 Chums 4 Drawing Figs ABSTRACT: A coil spring that is compressible along its lon- [5 2] US. Cl 197/17, gitudinal axis but relatively stiff alongits transverse axis is em- 197/16 ploycd to connect typewriter keylevers with power operating [5 l] Int. Cl B4lj 23/02 mechanisms so as to prevent multiple output operations from [50] a single depression.

Field of Search 197/16, l7

Patented Nov, 3, 1970 INVENTORS.

ALLISON H. CAUDILL WILLIE GOFF ,JR.

7 ATTORNY.

COIL SPRING NON-REPEAT KEYLEVER DOBBER DISCLOSURE OF THE INVENTION The key boards of power driven typewriters virtually universally include single action or nonrepeat connections or dobhers between most keylevers and the power devices which the keylevers control to insure that a single depression of a keylover will generate a single typewriter output. A further output can be obtained from that keylever only by release and redcprcssion. Occasionally it is desirable to allow multiple typewriter operations from a single depression of a kcylever, but even in such instances, a nonrepeat mechanism is provided for normal key operation and additional mechanism is included for bypassing the nonrepeat connection.

A common form of nonrepeat connection employs a pivoted link that is spring biased to a stable position between the keylever and a controlled power member for enabling keylever input motion to activate the power member. The power member moves independently. of the keylever to operate a typing operation and restores in a direction having a substantial component that is generally transverse to its initial input motion. In the event the keylever remains depressed as the power member is restored, the pivoted link is struck in a direction to move it against its spring bias. Pivot nonrepeat links basically include three parts: a bellcrank lever, a stud by which the lever is rotatably mounted, and a bias spring.

It is the primary objective-of this invention to accomplish the nonrepeat function with a single, very light coil spring to achieve a substantial simplification ofa typewriter keyboard.

Another object of this invention has been to provide an improved selectively effective mechanical connection employing the directional intelligenceof a coil spring as a discriminating factor to substantially simplify the construction of such connection.

We have discovered that a coil spring can be mounted to be relatively stable in its transverse or diametrical plane while being also resiliently weak in its longitudinal or axial plane. Our discovery is applied to a typewriter keyboard or the like by substituting for the usual pivoted spring biased bell crank, a single coil spring trapped between opposed tongs on either the keylever or controlled power member. The coil spring is oriented to present its transverse dimension for force transfer between the keylever and a power member. Restoring motion of the power member is permitted by the coil spring which simply yields upon being subjected to force along its longitudinal axis, if the keylever remains depressed upon completion of the power stroke.

These and other objects, features and advantages of our invention will be apparent from the following description of two specific embodiments of our invention, demonstrating not only the concepts of our basic invention but also some preferred structural details useful in enhancing those concepts.

ln the drawing:

FIG. 1 shows a cross-sectional view of i typewriter keyboard mechanism employing a coil spring dobber constructedin accordance with our invention;

FIG. 2 shows an enlarged fragmentary side view of a portion of a keyboard constructed like that of FIG. 1, but showing a prior art form of nonrepeat dobber;

FIG. 3 is an enlarged fragmentary view of the portion of the keyboard shown in FIG. 1 showing the spring coil dobber in two of its primary operating positions; and

FIG. 4 is a side cross-sectional view of a different form of typewriter illustrating a different application of our coil spring dobber.

Referring now more specifically to FIG. 1, there is shown a typewriter keyboard 10, having a plurality of keys 11 each mounted on an individual keylever or input member 12. Each keylever 12 is pivoted to the typewriter frame 13 by a wire 14. The keyboard is constructed substantially like that disclosed in U.S. Pat. No. 3,086,635, entitled Keylever Storage Mechanism," issued April 23, I963, to Leon E. Palmer. Each of the keylevers 12 isbiased upwardly by resilient means such as a leaf spring 15 to a normal inactive position defined by an upstop rod 16. Depression of a keylever 12 moves it to an active position shown in broken lines in H0. 3, against a downstop 17.

Below each keylever 12 is a power driven interposer 20 hav' ing an upstanding projection 21 positioned adjacent and below the keylever 12 for receiving downward force therefrom. Each of the interposcrs 20 is biased by a spring 22 upwardly and to the right to a normal inactive position wherein the right end 23 of the interposer is retained against a leaf spring latch 24. A keyboard power device or cycle clutch 30 is connected to-a continuously running motor shaft (not shown) and through gears 31, 32, 33 to a filter shaft or power member 34.

Cycle clutch 30 is normally held stationary by a latch 40 that engages one oftwo arresting ledges 35 on the clutch 30. A clutch control arm 41 is urged leftwardly by a spring 42 to tend to release latch 40 from ledge 35 of the cycle clutch 30. Motion from the spring 42 is normally restrained by a pivoted latch 43 that engages a frame carried keeper part 44 whenever no keylever 12 is depressed. Latch 43 is biased upwardly to a latching position by a spring 45. A ball 46 extends the width of the keyboard 10 and transfers downward motion from any interposer 20 to the latch 43 to release the control arm 41 and latch 40, thereby initiating a l rotation of cycle clutch 30 and filter shaft 34.

A cam 36, carried by the cycle clutch 30, engages follower arm 47 of latch 40 to restore the latch and the control arm 41 to their latched positions during rotation of cycle clutch 30. The cycle clutch latch 40 thus is positioned to intercept the next succeeding cycle clutch ledge 35 to terminate rotation after Upon depression of any keybutton 11, its associated interposer 20 is pivoted clockwise about a support rod 18 to a position where interposer end 23is free of leaf spring 24 and an intcrposer driving part 25 is aligned with a tooth 37 of the filter shaft 34. Upon rotation of cycle clutch 30 as described above, filter shaft 34 drives the displaced interposer 20 leftwardly as guided by its slot 26. This leftward displacement generates a keyboard output by leftward displacement of one or more output bails 27 as determined by the selected presence or absence of code projections 28 on the particular interposer involved. The output of bails 27 can operate a typewriter printing device as taught in U.S. Pat. No. 2,919,002 entitled, Selection Mechanism for a Single Printing Element Typewriter, issued to L. E. Palmer, Dec. 29, I959. As the interposer 20 is driven beyond the range of filter shaft tooth 37, the horizontal load thereon diminishes and spring 22 begins to restore the interposer upwardly and to the right to its normal position. It thus can be seen that each interposer 20 will follow a path generally as indicated by the chain line P in FIG. 1. Of particular significance is the initial motion or control input direction of movement P, and the line restore motion direction P Note that the directions P, and P are transverse to one another but not necessarily perpendicular. These transverse directions are relied on to provide nonrepeat discrimination.

FIG. 2 shows a keylever 50 like the keylever 12 of HO. 1, but having a prior art form of nonrepeat dobber 51. The motion direction lines P and P have been reproduced, together with a broken line position of the parts which represents the position of keylever 50 when held in its active position. The prior art dobber 51 includes a bellcrank 52 pivotally mounted by a stud 53 on the keylever 50 and biased by a spring 54 to a clockwise limit determined by bent-over tab 55 that engages the upper surface of keylever 50. The lower end 56 ofthe bellcrank 52 may also include a bent-over tab to increase the bearing surface for engaging the upstanding projection 21 of a typical interposer 20.

Depression of the keylever 50 will transfer force through bellcrank 52 to the interposer 20 to move the interposer downwardly thereby initiating a keyboard cycle as described in connection with FIG. 1. If the keylever 50 is held in its depressed (broken line) position when interposer 20 is returning along path P,, the upstanding end 21 of the interposer 20 will strike the rearward edge 57 of the bellcrank 52 and pivot the bellcrank 52 counterclockwise against its bias spring 54 to the broken line position shown. interposer 20 thus restores to its original position but is not reactuated since bellcrank 52 can no longer transfer. the downward position of'keylevcr 50 thereto. Keylever 50 must first be released to move upwardly by its spring whereupon spring 54 restores bellcrank 52 clockwise to its position as shown in full line in FIG. 2. After this release, the interposer can again be activated by depression of the same keylever 50.

The coil spring dobber or single action mechanical connection D of our invention is shown in FIG. 1 and is enlarged in FIG. 3 for comparison with.the prior art device of FIG. 2. 1n

' FIG. 3, keylever 12 is shown in its up or inactive position in full lines and in its depressed or activeposition in broken lines. The dobber D employs a simple coil spring 60 of circular cylindrical cross section and having a longitudinal axis 61 and a transverse axis 62. The coil spring 60 is mounted on a. connection part 70' of the keylever 12 by a pair of mutually inwardly directed opposed tongs or projections 71 and 72. Connection 70 provides a force transfer surface 73 for engaging a side edge of the coil spring 60. Projection 71 is spaced from surface 73 by a distance of approximately the same dimension as the thickness of wire from which spring 60 is made to define a slot 74 in which the spring is received. The coil spring 60 thus is normally held upwardly clear of the upstanding interposer projection 21. Thetong 72 is preferably of a vertical height to substantially fill or extend across the diameter of coil spring 60 to provide an added degree of lateral stability thereto. Compressive tension is retained in the spring 60 by end surface 75 and end surfaces 76 and 77 which are opposed thereto. End surface 75 is spaced from end surfaces 76 and 77 a distance less than the free or uncompressed length of the coil spring 60. Surfaces 76 and 77 engage the right longitudinal end face 63 of the coil spring at points spaced around its periphery, for example, as by 180 as shown, to further assist in providing an added degree ofstuhility to the spring.

'l'hc dobher D works in conjunction with part 00, which in H6. 3 comprises the upper part of interposer projection 21. The significant elements ofconnection part 00 are its upper or primary force transfer surface 81 and its leading edge or secondary force transfer surface 82. The primary surface 81 is mutually aligned with surface 73 of the connection part 70 and with the left longitudinal end 64 of the coil spring 60 to transfer at least a component of force therethrough along or substantially parallel to the transverse axis 62. The secondary surface 82 of the connection part 80 is engageable with the left longitudinal end 64 of spring 60 in a direction substantially parallel with the longitudinal spring axis 61 when keylever 12 is maintained in its depressed or active position so that no reactivating force can be transmitted back to the interposer 20 in input direction P,.

It can now be seen that depression of a keylever 12 will transfer force from surface 73 through approximately three coils of the left end 64 of the coil spring 60 and to the surface 81. interposer 20 thus will be again displayed along its input direction P to initiate a keyboard cycle as described in connection with FIG. 1. 1f keylever 12 is held depressed in its broken line position as' the interposer 20 returns along its restore path P the secondary surface 82 of connection part 80 will engage the left end 64 of the coil spring 60 in the direction of longitudinal axis 61 to compress the coil spring. As in the case of FIG. 2, interposer 20 will now have restored to its original position but it cannot be again depressed until keylever 12 is first released. Upon release of keylever 12, it will move upwardly by its spring 15 until the lower edge of the coil spring 60 clears the surface 82 whereupon spring 60 will again extend over the surface 81 of the projection 21 ready to receive a further depression.

Our coil spring nonrepeat connection can .also be employed in a different form of typewriter keyboard as illustrated in FIG. 4. HO. 4 shows a typcbar typewriter 90 of a generally known construction including a keyboard'91 having a plurality of keybuttons 92 each mounted on a keylever or input member 93 pivoted to the frame about a wire axis 94. The keylever 93 is normally urged against'an upstop 95 by a coil spring 96 to a normal or inactive position and is dcpressible to an active position defined by a downstop 97. A power cam 100 is engageable by a slight counterclockwise rotation with a continuously rotating power roll 101. Upon initial engagement with the power roll, cam 100 is rotated further counterclockwise driving its pivot, by which it is mounted on a cam lever 103, leftwardly. Cam lever 103 is pivoted to the frame about an axis 104 and pulls connecting link 105 to drive a typebar 106 through a free flight printing stroke. While the typebar 106 is in flight, cam 100 is lifted from the power roll 101 and permitted to restore clockwise under force of its spring 107. After impact, cam lever 103 is restored clockwise by its spring 108.

A coil spring nonrepeat connection or dobber D is provided in the embodiment of this typewriter by mounting a coil spring 110 between projections 111 like those shown in FIG. 3 in an extension 112 or connection part of the cam 100. The rightward end of coil spring 110 cooperates with a downwardly facing projection or connection part 113 of the keylever 93 to receive force along input direction P, therefrom for rotating cam about axis 102 into power roll 101. Restore motion of cam 100 and cam lever 103 moves the spring along a path P that is generally aligned with the spring longitudinal axis. Note that it is not necessary for the input and restore paths to be mutually perpendicular. it is only required that the coil spring 110 receive significant components of force in the input direction P,.

It can now be seen that a keylever 93' held against its downstop 97 will generate one typebar operation and coil spring 110 will encounter the rear edge 114 of projection 113 as it moves along its restore'path P Coil spring 110 thus will be compressed in a manner similar to that described in connection with FIG. 3 and no further output can be obtained from that power cum 100 until key lever 93 has been released to permit spring 110 to again expand to a position beneath projection 113.

From the foregoing description of our invention and of two specific applications thereof, it can be seen that we have provided a nonrepeat connection ofextreme simplicity and which is applicable to varied nonrepeat situations. it will also be seen that the active parts of our nonrepeat connection can be interchanged and reversed without departing from the concepts we have disclosed.

We claim:

1. A selective mechanical connection for controlling operation of a power driven member that is mounted for control input movement in a first direction and for restore movement in a second direction transverse to said first direction, by a movable input member having a normal inactive position and a selectable active position, wherein the improvement comprises:

a pair of connection parts, said connection parts of said pair being connected respectively to said power driven member and said input member;

a coil spring having a longitudinal axis',

means mounting said coil spring on one of said parts in an orientation presenting the longitudinal axis thereof substantially parallel to said sccond direction',

said one part having a force transfer surface for engaging said coil spring in a direction transverse to the longitudinal axis thereof;

the other of said parts having a primary force transfer surface for engaging said coil spring in a direction transverse to the longitudinal axis thereof for force transfer therethrough between said parts whenever said input member is moved from its inactive to its active position; and

said other part further having a secondary force transfer surface for force engaging said coil spring in a direction substantially parallel with its longitudinal axis, said secondary. force transfer surface being engageable with said coil spring only when said input member is in its active position.

2. A mechanical connection as defined in claim 1 wherein said coil spring mounting means comprises a pair of opposed end surface means formed on said one part for receiving respective longitudinal ends of said coil spring.

3. A mechanical connection as defined in claim 2 wherein at least one of said opposed end surface means of said coil spring mounting means includes means for engaging one longitudinal end of said coil spring at a plurality of spaced points thereon.

4. A mechanical connection as defined in claim 1 wherein said force transfer surface of said one part and said primary force transfer surface of said other part are substantiallymutually aligned in said first direction with one end of said coil spring. p

5. A mechanical connection as defined in claim 4 wherein said coil spring mounting means comprises a slot for closely engaging a sideedge portion of said one end of said coil spring to retain said coil spring out of contact with said other part whenever said input member is in its inactive position.

6. A mechanical connection as defined in claim 1 wherein said coil spring mounting means comprises a pair of mutually inwardly directed tongs for receiving the opposed ends of said coil spring therearound, said tongs having inward most ends that are mutually spaced to permit insertion of said coil spring therebetwcen.

7. A mechanical connection as defined in claim 6 wherein said coil spring is of circular cylindrical configuration and at least one of said tongs is dimensioned to extend substantially entirely across the inner diameter thereof.

8. A keyboard comprising a plurality of manually depressible keylevers, resilient means biasing said keylevers to a normal inactive position, downstop means for limiting the depression of said keylevers and defining an active position thereof, a

said coil spring in a direction transverse to the longitu dinal axis thereof;

the other of said parts having a primary force transfer surface for engaging said coil spring in a direction transverse to the longitudinal axis thereof for force transfer the'rethrough between said parts upon movement of said kcylever from its inactive to its active position; and

said other part further .having a secondary force transfer surface for engaging said coil spring in a direction substantially parallel with its longitudinal axis, said secondary force transfer surface being cngageable with said coil spring only when said input member is in its active position.

9. A keyboard as defined in claim 8 wherein said one part is operatively connected to said kcylever and said other part is operatively connected to said power driven member.

10. A keyboard as defined in claim 8 wherein said one part is operatively connected to said power driven member and said other part is operatively connected to said keylever.

11. A keyboard as defined in claim 8 wherein said force transfer surface of said one part and said primary force transfer surface of said other part are substantially mutually aligned in said first direction with one end of said coil spring.

2. A keyboard as defined in claim 9 wherein:

said force transfer surface of said one part and said primary force transfer surface of said other part are substantially mutually aligned in said first direction with one end of said coil spring; and

said coil spring mounting means comprises a slot for closely engaging a side edge portion of said one end of said coil spring to retain said coil spring out of contact with said other part whenever said kcylever is in its inactive position. t

13. A keyboard as defined in c aim 8 wherein:

said coil spring. is of circular cylindrical configuration;

saidcoil spring mounting means comprises a pair of mutually inwardly directed tongs for respectively receiving opposed ends of said coil spring thercaround;

said tongs have inwardmost ends that are mutually spaced 2 to permit insertion of said coil spring therebetween; and

at least one of said tongs is dimensioned to extend substantially entirely across the inner diameter of said coil spring. 

